Process of treating cotton fabric and product obtained thereby



Patented Apr. 10, 1923.

UNITED STATES.

PATENT OFFICE.

CHARLES LEONARD SCHUTTIG, OF RIDGEFIELD PARK, NEW JERSEY.

PROCESS .OF TREATING COTTON FABRIC AND PRODUCT OBTAINED THEREBY.

No Drawing.

ton Fabric and Product Obtained Thereby,

of which the following is a specification.

.This invention relates to the treatment of goods composed of cellulose fibres, i. e., cotton oods, and especially muslins, after the goods have been bleached, singed, and dried by known methods; and the product thereby obtained. My invention has for its object the production of afabric having what termed as a permanent finish. This is a stiffening property which adheres to the fabric throughout its life. and which cannot be .washed out, irrespective of the number or length of the washings.

The process which I employ in effecting this object is based on the fact that cellulose when treated with nitric acid in the presence of sulphuric acid, is converted into a chemical compound known as a cellulose nitrate, the composition of which is dependent upon the relative roportions of the acids used,

3 the strength of the acid solution, the duraof treatment. The so-call'ed lower cellulose nitrates produced by appropriate treatment have, when dry, a certain stiff property. It is this property which is made use of in this invention.

The process hereinafter set forth is utilized in the. production of this lower cellulose nitrate upon the surface of the fibres of the cellulose fabric, whereby to-change the surface of the cotton or cellulose fibre to cellulose nitrate, so that it will impart t0 the fabric its stiffening property.

For the purpose of illustration, I give the following specific example for the treatment of muslin. In this process I use a nitrating solution, whichpreferably should be prepared according to the following for- ,mula, i. e., v I

2 parts by weight, of 43 to *5", Baum, ni-

tric acid;

may be tion of treatment, and the temperature move the caustic soda.

Application filed September 11, 1919. Serial 1T0. 323,208.

ldpart by Weight, of 66, Baum, sulphuric aci The acids must be carefully and thoroughly mixed. The resultant solution will then have the following composition,

Nitric acid (100%) 50.0%;

Sulphuric acid (100%) 31.6%;

lVater 18.4%.

The solution mustbe cooled to 32 Fah. before it is ready to receive the goods. When the nitrating solution is sufficiently cool, the cotton fabric is passed through it by means of .rollers, or by the use of any other suitable instrumentalities, and is then passed immediately into a wash tank of 05 cold water. This operation must be accurately controlled, since the nitration must not be carried too far. The action must be so timed that the nitrating solution preferably will act upon the cotton fabric for a period not longer than from two to eight seconds, the time of immersion depending upon the quality and structure of the fabric and the finish desired. The instantthe fabric enters the nitrating solution, the action of the solution upon the fibres begins. and if this action were allowed to continue for too long a period, it would result in a brittle and weak product.

The purpose of the wash tank is to arrest the action of the nitrating solution at the proper time. p

As soon as the fabric has been passed through the wash tank, it is sent through a series of sprays of hot Water, in order to remove the least traces of the acid. The fabric is then passed through rollers or other suitable devices for expressing as much of .the" water as possible, and it is then treated with a finishing bath whichconsists in passing the goods through a solution of 40 to 45Baum, caustic soda. at atemperature of not more than 50 Fah. The fabric (saturated with the caustic) is then run onto a frame, stretched to its original width, and then passed through a hot water bath to re- This action must be so timed that the fabric remains saturated with the caustic soda for a period from one to two minutes. After washing, the fabric 1 to produce a stiffer material, it is necessary to repeat the treatment, and the desired degree of stiffness may be imparted to the fabric by giving it the requisite number of treatments.

The process which I utilize will produce upon cotton fabrics, a stiffness that is equal to that produced by the present methods of starch stiffening, and furthermore, the product will be superior to that produced by the starch methods, because it presents a. finer appearance than the starch fabrics, being more transparent. Furthermore, the product obtained by my process is very much superior to the product obtained by the present methods of starch stiffening, because the stiffness is of a permanent nature, being due to a. change effected on the surface of the fibres themselves, which does not alter their texture, and which, therefore, cannot Y be washed out.

An important feature of this invention is the conversion of the surface only of the cellulose fibres into'a lower cellulose nitrate.

Obviously the subsequent treatment of the fabric may be varied, so long as this end is attained, without departure from this part of the invention.

It is essentialto the proper practice of this invention. that the acid mixture be not allowed to penetrate and react with the entire body of the cotton, since this would produce a product that would be too tender to be of any commercial value. I have found that by running the goods at a very high speed through the acid mixture, and Washing the acid out of the fibres at a time that will have allowed the acid to react on the fibres for from one to two seconds, that a nitrate is produced on the veryout- 1 side surface of the fibres, and a slight stiffness results. The goods after having been treated with the caustic bath are dried,- and areagain given an acid treatment, this time the speed of the fabric through the acid mixture being such that the acid remains on the fibres for about from two to three seconds. This allows a little furtherpenetration of the acid into the fibres, and produces a greater de cc of stiffness in the goods. If a still stiffer finish is desired, further treatment with the acid and caustic solution is effected until the desired stiffness is obtained. I have .found that three treatments are about the limit for the production of the general run of finishes. Experience has shown that the desired finish is produced without in any way weakening the goods.

Having thus described my invention what I claim as new, and desire to secure by Letters Patent. is,

' 1. A process for imparting a finish to cotton fabrics which consists in subjecting the fabric to a nitrating solution whereby to composed of approximately two parts by weight of 43 to 45 Baum nitric acid, and approximately one part by weight, of {36 Baum sulphuric acid, for asuflicient period of time to convert the surfaces-of thefibres into a lower cellulose nit-rate, then arresting the action of the solution by treatment.

with water. and expressing the water from the fabric, then bathing the fabric in a solution of caustic soda, then washing the fabric to remove the caustic soda, then stretching and drying the fabric.

3. A process for. imparting a permanent finishjto fabric containing cellulose fibres, which comprises subjecting the fabric to a nitrating solution containing nitric and sul-. phuric acid for a sufficlent period to con-- vert-the surfaces only of the fibres into a lower cellulose nitrate, then arresting the action of the solution by treatment with water. then expressing the water from the fabric, then bathing the fabric in a solution of caustic soda. then washing the fabric to remove the caustic soda, and then stretching and drying the fabric.

4. A process for imparting a permanent finish to cotton fabric which comprises subjecting the fabric to a nitrating solution for a period sufficient to convert the surfaces of the fibres into a lower cellulose nitrate; arresting the action of the solution; bathing the fabric in a solution of caustic soda; then removing the caustic soda, and finally stretching and drying the fabric.

5. A process for imparting a permanent finish to fabric containing cotton cellulose fibres which comprises subjecting the fabric to a nitrat-ing solution, and arresting the'action of the solution when the surfaces of the fibres have been thereby converted into a lower cellulose nitrate, and before the fibres as a whole have been so converted.

6. A process for imparting a permanent finish to fabric containing cellulose fibres which 0 solution acid, in

ture, and for a sufiicient 5 convert lower cellulose nitrate,

the action of the solution.

5 menace omprises subjecting the fabric to e the surfaces of 7. A fabric composed of cellulose fibres,

the surfaces only of which have 1 verted i been connto a lower cellulose nitrate.

only of which have been bonvertcd into 8 A cotton fabric, the surfaces only of the fibres of which have been converted into a lower cellulose nitrate.

9., A fabric including fibres, the surfaces lower cellulose nitrate.

In testimony whereof I hereunto afiix my signature CHAR-LES LEONARD SCHUTTIG. 

